1. Technical Field
This disclosure relates to analog filters that are tunable to a desired frequency and to deviations in the value of components in each instance of the same filter due to process variations during their manufacture.
2. Description of Related Art
On-chip analog filters may be tunable over a wide frequency range based on a digital tuning signal that is indicative of a frequency of a desired filter characteristic, such as a desired center or cut-off frequency. This degree of tuning that is done in response to various digital tuning signals may need to be calibrated due to deviations in the value of components in the analog filter caused by process variations during its manufacture, such as deviations in the values of resistors, capacitors, and/or inductors.
Trim values can be applied to correct for these component value deviations. However, the trim needed for some tunable analog filters, such as binary-weighted tunable analog filters, may depend upon the desired frequency setting. The need to have different trim values for different frequency settings can add considerable complexities and costs.